The detection of locking of a free running oscillator (FRO) is disclosed, including taking periodic samples of the FRO output, storing each new sample in a sample storage medium, each time a new sample is stored searching the stored samples for at least one repeating pattern, counting consecutive sampling instances in which a repeating pattern is found, and indicating when the count reaches a preselected threshold number.
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1. A device for detecting locking of a free running oscillator (FRO), comprising: a sampler configured to take periodic samples of an output of the FRO; a sample storage medium coupled to the sampler and configured to store a plurality of consecutive samples of the output of the FRO; a first pattern detector coupled with the sample storage medium, the first pattern detector being configured to, in response to a new sample being stored in the sample storage medium, detect, in the plurality of consecutive samples of the output of the FRO, repeating patterns of a first length; a second pattern detector coupled with the sample storage medium in parallel with the first pattern detector, the second pattern detector being configured to, in response to the new sample being stored in the sample storage medium, detect, in the plurality of consecutive samples of the output of the FRO, repeating patterns of a second length, the second length being different than the first length; an error counter coupled with the first pattern detector and the second pattern detector, the error counter being configured to count instances of detected repeating patterns; a threshold detector coupled to the error counter, the threshold detector being configured to output a FRO lock indication signal when the error counter reaches a preselected number of instances of detected repeating patterns, the preselected number being greater than or equal to one; and a FRO adjuster configured to adjust the FRO in response to the FRO lock indication signal.
A system detects when a Free Running Oscillator (FRO) becomes locked. It periodically samples the FRO's output and stores these samples. Two pattern detectors analyze these stored samples. One looks for repeating patterns of a specific length, while the other searches for repeating patterns of a different length. If either detector finds a repeating pattern, an error counter increments. When this counter reaches a set threshold, it signals that the FRO is locked. The system then adjusts the FRO, potentially restarting it, shutting it down, or changing its frequency.
2. The device of claim 1 , wherein the device is embodied on an application specific integrated circuit (ASIC).
The FRO locking detection device, which includes a sampler to periodically take samples of the FRO's output, a sample storage to store consecutive samples, two pattern detectors to detect repeating patterns of different lengths in the samples, an error counter to count repeating patterns, a threshold detector to output a lock indication, and an FRO adjuster to adjust the FRO, is implemented on an Application Specific Integrated Circuit (ASIC). This means the entire system is integrated into a single, custom-designed chip.
3. The device of claim 1 , further comprising a data storage configured to store an indication that the preselected number of instances of detected repeating patterns was detected.
The FRO locking detection device, which includes a sampler to periodically take samples of the FRO's output, a sample storage to store consecutive samples, two pattern detectors to detect repeating patterns of different lengths in the samples, an error counter to count repeating patterns, a threshold detector to output a lock indication, and an FRO adjuster to adjust the FRO, also includes a data storage. This data storage records when the error counter reaches the pre-selected threshold, indicating a FRO lock event has been detected. This allows the system to maintain a record of lock detections.
4. The device of claim 1 , further comprising an alarm generator configured to generate an alarm when the threshold detector indicates the preselected number of instances of detected repeating patterns has been reached.
The FRO locking detection device, which includes a sampler to periodically take samples of the FRO's output, a sample storage to store consecutive samples, two pattern detectors to detect repeating patterns of different lengths in the samples, an error counter to count repeating patterns, a threshold detector to output a lock indication, and an FRO adjuster to adjust the FRO, further includes an alarm generator. This alarm generator is triggered when the threshold detector indicates the pre-selected number of repeating pattern instances has been reached. This generates an alert, signaling a potential FRO lock.
5. The device of claim 1 , wherein adjusting the FRO includes at least one of restarting the FRO, shutting down the FRO, and changing an operating frequency of the FRO.
In the FRO locking detection device, which includes a sampler to periodically take samples of the FRO's output, a sample storage to store consecutive samples, two pattern detectors to detect repeating patterns of different lengths in the samples, an error counter to count repeating patterns, a threshold detector to output a lock indication, and an FRO adjuster, the FRO adjuster responds to the FRO lock indication signal by either restarting the FRO, shutting down the FRO entirely, or changing the FRO's operating frequency. This allows for different strategies to correct the locked FRO.
6. The device of claim 1 , further comprising a threshold level selector configured to change the preselected number.
The FRO locking detection device, which includes a sampler to periodically take samples of the FRO's output, a sample storage to store consecutive samples, two pattern detectors to detect repeating patterns of different lengths in the samples, an error counter to count repeating patterns, a threshold detector to output a lock indication, and an FRO adjuster to adjust the FRO, also has a threshold level selector. This selector allows for changing the preselected number of instances of repeating patterns required to trigger the lock indication. This adjusts the sensitivity of the lock detection.
7. The device of claim 1 , wherein the sample storage medium includes a shift register.
In the FRO locking detection device, which includes a sampler to periodically take samples of the FRO's output, two pattern detectors to detect repeating patterns of different lengths in the samples, an error counter to count repeating patterns, a threshold detector to output a lock indication, and an FRO adjuster to adjust the FRO, the sample storage medium, which stores a plurality of consecutive samples of the output of the FRO, is implemented using a shift register. A shift register allows for efficient storage and updating of the sample history.
8. The device of claim 1 , wherein: detecting, by the first pattern detector or the second pattern detector, repeating patterns includes comparing a respective number of most recent samples of the plurality of consecutive samples of the output of the FRO with a same number of immediately preceding samples of the plurality of consecutive samples of the output of the FRO, and incrementing the error counter includes incrementing the error counter when at least one of the first pattern detector and the second pattern detector determines that a pattern of the most recent samples is the same as a pattern of the immediately preceding samples.
In the FRO locking detection device, which includes a sampler to periodically take samples of the FRO's output, a sample storage to store consecutive samples, two pattern detectors to detect repeating patterns of different lengths in the samples, an error counter to count repeating patterns, a threshold detector to output a lock indication, and an FRO adjuster to adjust the FRO, the pattern detectors compare the most recent samples with the immediately preceding samples. If a pattern matches, the error counter increments. This allows for detection of repeating patterns indicating a locked state.
9. The device of claim 8 , wherein the error counter is configured to reset to zero when neither of the first pattern detector and the second pattern detector detect a repeating pattern in response to the new sample being stored in the sample storage medium.
Building upon the FRO locking detection device where pattern detectors compare recent and preceding samples, incrementing an error counter on a match, the error counter resets to zero if neither pattern detector finds a repeating pattern when a new sample is added. This prevents the error counter from accumulating false positives and ensures it accurately reflects consecutive instances of detected repeating patterns, contributing to more reliable lock detection.
10. The device of claim 1 , wherein an operating frequency of the FRO is greater than or equal to one-half a frequency at which the sampler takes the periodic samples of the output of the FRO.
In the FRO locking detection device, which includes a sampler to periodically take samples of the FRO's output, a sample storage to store consecutive samples, two pattern detectors to detect repeating patterns of different lengths in the samples, an error counter to count repeating patterns, a threshold detector to output a lock indication, and an FRO adjuster to adjust the FRO, the operating frequency of the FRO must be at least one-half the frequency at which the sampler takes periodic samples. This ensures sufficient sampling to accurately detect FRO locking.
11. A method of detecting locking of a Free Running Oscillator (FRO), the method comprising: periodically sampling an output of the FRO at a sampling frequency; storing a plurality of consecutive samples of the output of the FRO in a sample storage medium; in response to a new sample being stored: detecting, with a first pattern detector, repeating patterns of a first length in the plurality of consecutive samples of the output of the FRO; and detecting, with a second pattern detector, repeating patterns of a second length in the plurality of consecutive samples of the output of the FRO; in the event at least one repeating pattern is found, counting a number of consecutive sampling instances in which a repeating pattern is found; detecting when the count of the number of consecutive sampling instances in which a repeating pattern is found reaches a preselected threshold number; in response to the preselected threshold number being reached, outputting an FRO lock indication signal based thereon; and adjusting the FRO in response to the FRO lock indication signal.
A method detects when a Free Running Oscillator (FRO) locks. It samples the FRO's output at a specific frequency and stores consecutive samples. Two pattern detectors analyze these samples, one searching for repeating patterns of a first length, the other for patterns of a second length. If either finds a pattern, a counter increments. When this counter reaches a threshold, it outputs a lock indication signal, triggering an adjustment to the FRO, possibly restarting it, shutting it down, or changing its frequency.
12. The method of claim 11 , further comprising resetting the count of the number of consecutive sampling instances in which a repeating pattern is found to zero in the event repeating patterns are not found.
In the FRO locking detection method that samples the FRO output, stores samples, uses two pattern detectors, counts repeating patterns, and adjusts the FRO when a threshold is reached, the count of consecutive repeating pattern instances is reset to zero if no repeating patterns are found. This prevents false lock detections by ensuring the counter only reflects consecutive instances of actual repeating patterns.
13. The method of claim 11 , further comprising generating an alarm when the count of the number of consecutive sampling instances in which a repeating pattern is found reaches the threshold number.
In the FRO locking detection method that samples the FRO output, stores samples, uses two pattern detectors, counts repeating patterns, and adjusts the FRO when a threshold is reached, an alarm is generated when the count of consecutive repeating pattern instances reaches the predefined threshold. This provides a notification when a FRO lock condition is detected.
14. The method of claim 11 , further comprising adjusting the FRO by one of restarting the FRO, shutting down the FRO, and changing an operating frequency of the FRO.
Within the FRO locking detection method, which involves sampling the FRO output, storing samples, employing two pattern detectors, counting repeating patterns, and outputting a lock indication signal upon reaching a threshold, adjusting the FRO includes the option of restarting the FRO, shutting down the FRO, or changing the operating frequency of the FRO. This allows for flexibility in how the system responds to a detected lock condition.
15. The method of claim 11 , further comprising modifying a sensitivity of the detector by changing the preselected threshold number.
The FRO locking detection method, involving sampling the FRO output, storing samples, employing two pattern detectors, counting repeating patterns, and outputting a lock indication signal upon reaching a threshold, also allows for modifying the detector's sensitivity. This is achieved by changing the preselected threshold number. Higher thresholds require more consecutive repeating patterns to trigger a lock indication, making the detection less sensitive.
16. The method of claim 11 , wherein an operating frequency of the FRO is greater than or equal to the sampling frequency.
Within the FRO locking detection method that involves sampling the FRO output, storing samples, employing two pattern detectors, counting repeating patterns, and outputting a lock indication signal upon reaching a threshold, the operating frequency of the FRO must be greater than or equal to the sampling frequency. This guarantees that the sampling rate is high enough to capture the behavior of the FRO and accurately detect locking.
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January 6, 2009
March 14, 2017
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